In theory, and even more in the practice of sustainability communications, the gender dimension of sustainability has been neglected relative to other fields of the science. The aim of this paper is to show the relevance of gender as an analytical category for research and the importance of gender competence as an indispensable skill for professional sustainability communicators. Understanding how gender norms have contributed to inhibiting sustainable development is key to well-targeted means to communicate visions of sustainable ways of life. Traditional norms of masculinity are clearly in tension with the ethical, ecological and social implications of Sustainable Development, whereas the norms of femininity work against empowerment and participation of women. Current changes in gender relations and gender identities in the western world do not automatically solve this conflict of norms. Therefore, sustainability communication must and can contribute to shaping the social construction of gender towards new “sustainable” norms and ideals for the various gender identities in western societies. In order to achieve this, gender mainstreaming (GM) needs to be implemented in the field of sustainability communication, from capacity building for communicators to project design and research. Gender and diversity competence is to become a professional requirement, assuring that traditional “doing gender” is avoided, cultural diversity respected and structural inequalities are made visible. Visions of sustainable societies should include changes in gender relations. The argument is based on sociological studies, gender theories, gender policies, and environmental and sustainability communication studies, empirically supported by biographical studies and media analyses over the last twenty years in Western Europe, mainly Germany.